Living Shoreline in Ocean County, NJ Voted “Best Green Project”

Photo by Jason Worth

The Iowa Court and South Green Living Shoreline Project in Little Egg Harbor and Tuckerton, NJ, was awarded “Best Green Project” by Engineering News-Record magazine. The project is recognized for its use of innovative techniques to install new features to restore damage from Hurricane Sandy and protect the area from future storms.

In 2012, Superstorm Sandy devastated communities throughout New Jersey and the entire eastern seaboard. Storm resilience, flood mitigation, and shoreline restoration have since become top priorities for coastal communities and low-lying areas.

The Township of Little Egg Harbor, in conjunction with local partners including the Borough of Tuckerton, was the recipient of a $2.13 million Hurricane Sandy Coastal Resiliency Competitive Grant through the National Fish and Wildlife Foundation for a Marsh Restoration and Replenishment project. The grant was secured by New Jersey Future. The purpose of the project was to restore and replenish local marsh, wetlands, and beaches suffering extensive erosion along the shoreline.

T&M Associates, as the Municipal Engineer of Record for the project, oversaw all aspects of the design and implementation. T&M contracted Princeton Hydro to perform sediment sampling/testing and conduct hydrographic surveys, and Arthur Chew Consulting to assist with the feasibility study and design of the dredging project.

The project, which was completed in September 2019, provides long-term protection from erosion and will restore the vegetated shoreline habitats through strategic placement of plants, stone, sand fill, and other structural and organic materials. The living shoreline will help in the areas of storm protection, flood mitigation, and combatting shoreline erosion. The project was a great success for the Little Egg Harbor and Tuckerton communities.

Photo by Jason Worth

Since the restoration of Iowa Court and South Green Street, this living shoreline model has received significant attention and praise, including in the American Council of Engineering Companies of New Jersey 2020 Engineering Excellence Awards; the New Jersey Society of Municipal Engineers 2019 Project of the Year Awards; and, now, this “Best Green Project” award from Engineering News-Record.

“There is growing interest in this approach from municipalities up and down the Jersey Shore. Storm and flood damage is still a pressing threat to hundreds of towns and boroughs, and it is widely accepted that storms like Sandy will only become more frequent due to the effects of climate change,” said Jason Worth, P.E., Group Manager at T&M Associates. “Thankfully, there is hope in innovation and creativity – with new approaches to living shorelines we can breathe life back into devastated beachfront communities and the natural ecosystems that support them.”

Princeton Hydro specializes in the planning, design, permitting, implementing, and maintenance of coastal rehabilitation projects. To learn more about some of our ecosystem restoration and enhancement services, visit: bit.ly/PHcoastal.

Photo by Jason Worth

UPDATE: NJ’s Dunes at Shoal Harbor Shoreline is Restored

The Dunes at Shoal Harbor, a coastal residential community in Monmouth County, New Jersey, is situated adjacent to both the Raritan Bay and the New York City Ferry channel.  In July 2018, Princeton Hydro was contracted to restore this coastal community that was severely impacted by Hurricane Sandy. Today, we are thrilled to report that the shoreline protection design plans have been fully constructed and the project is complete.

Rendering of the shoreline protection design
September 2020
A rendering of the shoreline protection design by Princeton Hydro. A snapshot of Princeton Hydro's completed work in September 2020.

In order to protect the coastal community from flooding, a revetment had been constructed on the property many years ago. The revetment, however, was significantly undersized and completely failed during Hurricane Sandy. The community was subjected to direct wave attack and flooding, homes were damaged, beach access was impaired, and the existing site-wide stormwater management basin and outfall was completely destroyed.

July 2018
September 2020

Princeton Hydro performed a wave attack analysis commensurate with a category three hurricane event and used that data to complete a site design for shoreline protection.

The site design and construction plans included:

  • The installation of a 15-foot rock revetment (one foot above the 100-year floodplain elevation) constructed with four-foot diameter boulders;

  • The replacement of a failed elevated timber walkway with a concrete slab-on-grade walkway, restoring portions of the existing bulkhead, clearing invasive plants, and the complete restoration of the failed stormwater basin and outlet; and

  • The development of natural barriers to reduce the impacts of storm surges and protect the coastal community, including planting stabilizing coastal vegetation to prevent erosion and installing fencing along the dune to facilitate natural dune growth.

These measures will prevent shoreline erosion, protect the community from wave attacks and flooding, and create a stable habitat for native and migratory species.

During the final walkthrough earlier this month, the Princeton Hydro team captured drone footage of the completed project site. Click below to watch the video:

For more images and background information on this project, check out the following photo gallery and read our original blog post from July 2018:

Conservation Spotlight: Dunes at Shoal Harbor Shoreline Protection

For more information about Princeton Hydro’s engineering services, go here.

Analyzing Mitigation Strategies for Flood-Prone Philadelphia Community

Photo from Eastwick Friends and Neighbors Coalition

Hydrology is the study of the properties, distribution, and effects of water on the Earth’s surface, in the soil and underlying rocks, and in the atmosphere. The hydrologic cycle includes all of the ways in which water cycles from land to the atmosphere and back. Hydrologists study natural water-related events such as drought, rainfall, stormwater runoff, and floods, as well as how to predict and manage such events. On the application side, hydrology provides basic laws, equations, algorithms, procedures, and modeling of these events.

Hydraulics is the study of the mechanical behavior of water in physical systems. In engineering terms, hydraulics is the analysis of how surface and subsurface waters move from one point to the next, such as calculating the depth of flow in a pipe or open channel. Hydraulic analysis is used to evaluate flow in rivers, streams, stormwater management networks, sewers, and much more.

Combined hydrologic and hydraulic data, tools, and models are used for analyzing the impacts that waterflow – precipitation, stormwater, floods, and severe storms – will have on the existing infrastructure. This information is also used to make future land-use decisions and improvements that will work within the constraints of the hydrologic cycle and won’t exacerbate flooding or cause water quality impairment.

Simply put, hydrologic and hydraulic modeling is an essential component of any effective flood risk management plan.

Putting Hydrologic & Hydraulic Analysis to Work in Philadelphia

Eastwick, a low-lying urbanized neighborhood in Southwest Philadelphia, is located in the Schuylkill River Watershed and is almost completely surrounded by water: The Cobbs and Darby creeks to the west, the Delaware River and wetlands to the south, and the Schuylkill River and Mingo Creek to the east. The community is at continual risk of both riverine and coastal flooding, and faces an uncertain future due to sea level rise and riverine flooding exacerbated by climate change.

Princeton Hydro, along with project partners KeystoneConservation and University of Pennsylvania, conducted an analysis of Eastwick, the flood impacts created by the Lower Darby Creek, and the viability of several potential flood mitigation strategies.

Flood mitigation approaches can be structural and nonstructural. Structural mitigation techniques focus on reconstructing landscapes, including building floodwalls/seawalls and installing floodgates/levees. Nonstructural measures work to reduce damage by removing people and property out of risk areas, including zoning, elevating structures, and conducting property buyouts.

For Eastwick, studying stream dynamics is a key component to determining what type of flood mitigation strategies will yield the most success, as well as identifying the approaches that don’t work for this unique area.

Princeton Hydro Senior Ecologist Christiana Pollack CFM, GISP participated in a workshop for Eastwick residents held by CCRUN and the Lower Darby Creek team. The goal of the workshop was to get the community’s input on the accuracy of the predictive models.Princeton Hydro’s study focused on the key problem areas in Eastwick: the confluence of Darby Creek and Cobbs Creek; a constriction at Hook Road and 84th Street; and the Clearview Landfill, which is part of the Lower Darby Creek Superfund site. Additionally, the study sought to answer questions commonly asked by community members related to flooding conditions, with the main question being: What impact does the landfill have on area flooding?

The built-up landfill is actually much higher than the stream bed, which creates a major disconnection between the floodplain and the stream channel. If the landfill didn’t exist, would the community still be at risk? If we increased the floodplain into the landfill, would that reduce neighborhood flooding?

Princeton Hydro set out to answer these questions by developing riverine flooding models primarily using data from US Army Corps of Engineers (USACE), Federal Emergency Management Agency (FEMA), The National Oceanic and Atmospheric Administration (NOAA), and NOAA’s National Weather Service (NWS). FEMA looks at the impacts of 1% storms that are primarily caused by precipitation events as well as coastal storms and storm surge. NOAA looks at the impacts of hurricanes. And, NOAA’s NWS estimates sea, lake and overland storm surge heights from hurricanes.

This is an example of a 2D model showing where the water is originating, how the water flows through the neighborhood, moves to the lower elevations, and eventually sits.

This is an example of a 2D model showing where the water is originating, how the water flows through the neighborhood, moves to the lower elevations, and eventually sits.

The models used 2D animation to show how the water flows in various scenarios, putting long-held assumptions to the test.

The models looked at several different strategies, including the complete removal of the Clearview Landfill, which many people anticipated would be the silver bullet to the area’s flooding. The modeling revealed, however, that those long-held assumptions were invalid. Although the landfill removal completely alters the flood dynamics, the neighborhood would still flood even if the landfill weren’t there. Additionally, the modeling showed that the landfill is actually acting as a levee for a large portion of the Eastwick community.

This model was developed to illustrate how the removal of the landfill impacts waterflow through the Eastwick community.

This model was developed to illustrate how the removal of the landfill impacts waterflow through the Eastwick community.

Ultimately, the research and modeling helped conclude that for the specific scenarios we studied, altering stream dynamics – a non-structural measure – is not a viable flood mitigation strategy.

The USACE is currently undergoing a study in collaboration with the Philadelphia Water Department to test the feasibility of a levee system (a structural control measure), which would protect the Eastwick community by diverting the flood water. Funding for the study is expected to be approved in the coming year.

Take a Deeper Look at Eastwick Flood Mitigation Efforts

There are many studies highlighting flood mitigation strategies, environmental justice, and climate change vulnerability in Eastwick. Princeton Hydro Senior Project Manager and Senior Ecologist, Christiana Pollack CFM, GISP, presented on the flooding in Eastwick at the Consortium for Climate Risk in the Urban Northeast Seminar held at Drexel University. The seminar also featured presentations from Michael Nairn of the University of Pennsylvania Urban Studies Department, Ashley DiCaro of Interface Studios, and Dr. Philip Orton of Stevens Institute of Technology.

You can watch the full seminar here:

For more information about Princeton Hydro’s flood management services, go here: http://bit.ly/PHfloodplain.

Setting the Precedent: Blue Acres Floodplain Restoration in Linden

The City of Linden, located 13 miles southwest of Manhattan in Union County, New Jersey, is a highly urbanized area with a complex mix of residential, commercial, and industrial land uses. Originally settled as farmland on broad marshes, the City has deep roots in industrial production that emerged in the 19th century, and its easily accessible location on the Arthur Kill tidal straight helped fuel this industrial development.

Now, the City of Linden, which is home to more than 40,000 people, is considered a transportation hub: it has three major highways running through it (the New Jersey Turnpike, Route 1, and Route 27); its rail station provides critical commuter and industry access; the Linden Municipal Airport is a gateway to the NY/NJ metropolitan area; and its access point on the Arthur Kill is used by shipping traffic to the Port Authority of NY and NJ.

Unfortunately, the industrial boom left a legacy of pollution in the city, so much, that the Tremley Point Alliance submited an official Envionmental Justice Petition to the state. In 2005, the New Jersey Environmental Task Force selected the community for the development of an Environmental Justice Action Plan and listed it as one of six environmental justice communites in New Jersey.

As do many urban municipalities, Linden suffers severe flooding from heavy rains and storms. One of the significant sources of flood water threatening the City comes from stormwater runoff.

Like other communities in the Arthur Kill Watershed, Linden also suffers severe flooding from heavy rains and storms with one of the significant sources of flood water coming from stormwater runoff. Due to a high percentage of impervious cover from houses, roadways, and sidewalks, even small rain events generate a significant amount of stormwater runoff. Over time, these conditions have been exacerbated by the historic loss of coastal wetlands and outdated infrastructure. Nuisance flooding is especially problematic as runoff cannot drain from the area at a sufficient rate to prevent flooding during normal or elevated tidal conditions. Very simply, heavy rainfall is one factor contributing to recurring flooding.

In 2012, Hurricane Sandy caused wide-spread destruction throughout New Jersey and the entire eastern seaboard. The City of Linden was hard hit, and the City’s Tremley Point neighborhood was especially storm-ravaged. Tremley Point, a low-lying community of about 275 homes located at the headwaters of Marshes Creek and in the 100-year floodplain of the Rahway River, is regularly flooded during normal rain events. During Hurricane Sandy, local news outlets reported that a 15-foot tidal surge overtook Tremley Point homes, destroyed roads, and washed up hazardous material such as a 150-gallon diesel tank.

To help communities like Tremley Point recover, the New Jersey Department of Environmental Protection (NJDEP) launched the Blue Acres program under which NJDEP purchases homes from willing sellers at pre-Sandy market values, so residents in areas of repetitive and catastrophic flooding can rebuild their lives outside flood-prone areas. Structures are demolished and the properties are permanently preserved as open space for recreation or conservation purposes. The program began in 1995 and expanded with federal funding after Sandy. The goal of the Blue Acres Program is to dramatically reduce the risk of future catastrophic flood damage and to help families to move out of harm’s way.

As part of the NJDEP Blue Acres Program, Princeton Hydro, in collaboration with the City of Linden, Rutgers University, NJDEP, Phillips 66, National Fish and Wildlife Foundation, New Jersey Corporate Wetlands Restoration Partnership, and Enviroscapes, has undertaken one of the first ecological restoration projects within Blue Acres-acquired properties, which are located in the Tremley Point neighborhood. This project increases storm resiliency by reducing flooding and stormwater runoff by improving the ecological and floodplain function within the former residential properties acquired by the NJDEP Blue Acres Program.

The City of Linden Blue Acres restoration project increases storm resiliency by reducing flooding and stormwater runoff by improving the ecological and floodplain function within the former residential properties acquired by the NJDEP Blue Acres Program.

The project includes the development and implementation of an on-the-ground green infrastructure-focused floodplain enhancement design involving the restoration of native coastal floodplain forest and meadow, as well as floodplain wetlands. The restored area provides natural buffering to storm surge and enhances floodplain functions to capture, infiltrate, store, and slow excess stormwater to reduce the risk of future flood damage. In addition, it restores natural habitat and provides public recreation access on NJDEP Blue Acres property.

The design includes re-planting the parcels and the installation of a walking path through part of the area. It also includes the creation of a floodplain bench for the adjacent drainage ditch, an unnamed tributary to Marshes Creek. A floodplain bench is a low-lying area adjacent to a stream or river constructed to allow for regular flooding in these areas. Site improvements include grading of the floodplain bench and minor depressional area; 6-12-inches of tilling, soil amendment, and planting within the planting area; and construction of the gravel pathway.

The project will result in valuable environmental and community benefits to the area, including an annual reduction in stormwater runoff of 4.1 million gallons. This represents a 45% reduction in stormwater runoff. Restoration of the floodplain will also help reduce community vulnerability to storms. The hope is that this project will be a model that fosters more floodplain restoration projects in the future.

For more information on the Blue Acres Program, please visit the DEP website.

A Day in the Life of a Stormwater Inspector

Walking through a park isn’t always a walk in the park when it comes to conducting stormwater inspections. Our team routinely spots issues in need of attention when inspecting stormwater infrastructure; that’s why inspections are so important.

Princeton Hydro has been conducting stormwater infrastructure inspections for a variety of municipalities in the Mid-Atlantic region for a decade, including the City of Philadelphia. We are in our seventh year of inspections and assessments of stormwater management practices (SMPs) for the Philadelphia Water Department. These SMPs are constructed on both public and private properties throughout the city and our inspections focus on areas served by combined sewers. 

Our water resource engineers are responsible for construction oversight, erosion and sediment control, stormwater facilities maintenance inspections, and overall inspection of various types of stormwater infrastructure installation (also known as “Best Management Practices” or BMPs).

The throat of a sinkhole observed by one of our engineers while on site.

Our knowledgeable team members inspect various sites regularly, and for some municipalities, we perform inspections on a weekly basis. Here’s a glimpse into what a day of stormwater inspection looks like:

The inspector starts by making sure they have all their necessary safety equipment and protection. For the purposes of a simple stormwater inspection the Personal Protection Equipment (PPE) required includes a neon safety vest, hard hat, eye protection, long pants, and boots. Depending on the type of inspection, our team may also have to add additional safety gear such as work gloves or ear plugs. It is recommended that inspectors hold CPR/First Aid and OSHA 10 Hour Construction Safety training certificates. 

Once they have their gear, our inspection team heads to the site and makes contact with the site superintendent. It’s important to let the superintendent know they’re there so that 1) they aren’t wondering why a random person is perusing their construction site, and 2) in case of an emergency, the superintendent needs to be aware of every person present on the site.

Once they arrive, our team starts by walking the perimeter of the inspection site, making sure that no sediment is leaving the project area. The team is well-versed in the standards of agencies such as the Pennsylvania Department of Environmental Protection, the Pennsylvania Department of Transportation, the New Jersey Department of Environmental Protection, and local County Soil Conservation Districts, among others. These standards and regulations dictate which practices are and are not compliant on the construction site.

After walking the perimeter, the inspection team moves inward, taking notes and photos throughout the walk. They take a detailed look at the infrastructure that has been installed since the last time they inspected, making sure it was correctly installed according to the engineering plans (also called site plans or drainage and utility plans). They also check to see how many inlets were built, how many feet of stormwater pipe were installed, etc.

If something doesn’t look quite right or needs amending, our staff makes recommendations to the municipality regarding BMPs/SMPs and provides suggestions for implementation.

One example of an issue spotted at one of the sites was a stormwater inlet consistently being inundated by sediment. The inlet is directly connected o the subsurface infiltration basin. When sediment falls through the inlet, it goes into the subsurface infiltration bed, which percolates directly into the groundwater. This sediment is extremely difficult to clean out of the subsurface bed, and once it is in the bed, it breaks down and becomes silt, hindering the function of the stormwater basin.

To remedy this issue, our inspection team suggested they install stone around the perimeter of the inlet on three sides. Although this wasn’t in the original plan, the stones will help to catch sediment before entering the inlet, greatly reducing the threat of basin failure.

Once they’ve thoroughly inspected the site, our team debriefs the site superintendent with their findings. They inform the municipality of any issues they found, any inconsistencies with the construction plans, and recommendations on how to alleviate problems. The inspector will also prepare a Daily Field Report, summarizing the findings of the day, supplemented with photos.

In order to conduct these inspections, one must have a keen eye and extensive stormwater background knowledge. Not only do they need to know and understand the engineering behind these infrastructure implementations, they need to also be intimately familiar with the laws and regulations governing them. Without these routine inspections, mistakes in the construction and maintenance of essential stormwater infrastructure would go unnoticed. Even the smallest overlook can have dangerous effects, which is why our inspections team works diligently to make sure that will not happen.

Our team conducts inspections for municipalities and private entities throughout the Northeast. Visit our website to learn more about our engineering and stormwater management services.

 

PHOTOS: #BagThePhrag Update from Roebling Park

We’re gearing up for another invasive species treatment event at Roebling Park!

Located in Hamilton Township, New Jersey, Mercer County’s John A. Roebling Memorial Park offers residents in the surrounding area a freshwater marsh with river fishing, kayaking, hiking, and wildlife-watching. The park contains the northernmost freshwater tidal marsh on the Delaware River, Abbott Marshland. Since the mid-1990s, many public and private partnerships have developed to help support the preservation of this important and significant marsh.

Our Field Operations Team was recently at the project site assessing present invasive species and re-evaluating access points for our treatment equipment. Check out these photos from their visit!

 

For more information on this marsh restoration project at John A. Roebling Park, visit our original project blog:

Restoring the Northernmost Freshwater Tidal Marsh on the Delaware River

Urban Wetland Restoration to Yield Flood Protection for Bloomfield Residents

As part of the Third River Floodplain Wetland Enhancement Project,
a disturbed, flood-prone industrial site will be converted into a thriving public park.

Along the Third River and Spring Brook, two freshwater tributaries of the Passaic River, a disturbed industrial site is being transformed into 4.2 acres of wetlands, restoring the natural floodplain connection, enhancing aquatic habitat, and increasing flood storage capacity for urban stormwater runoff. The groundbreaking ceremony for this important ecological restoration project for Bloomfield Township took place last month.

“The Third River Floodplain Wetland Enhancement Project is a unique, creative solution that will transform a highly-disturbed, flood-prone, former industrial site into a thriving public park allowing for both passive and active recreational activities,” said Mark Gallagher, Vice President of Princeton Hydro. “By removing a little over four acres of upland historic fill in this densely developed area and converting it to a functioning floodplain wetland, the project will restore valuable ecological functions, increase flood storage capacity, and enhance wildlife habitat.”

Princeton Hydro is serving as the ecological engineer to Bloomfield Township for the Third River Floodplain Wetland Enhancement Project. Princeton Hydro’s scientists and engineers have assisted in obtaining grants, collected background ecological data through field sampling and surveying, created a water budget, completed all necessary permitting, and designed both the conceptual and final restoration plans. Additionally, Princeton Hydro will be conducting construction oversight during the implementation of this important urban wetland creation project.

The site includes 1,360 feet along the east bank of the Third River and 3,040 feet along the banks of the Spring Brook. These waterways are freshwater tributaries of the Passaic River and share a history of flooding above the site’s 100-year flood plain. The Third River, like many urban streams, tends to be the victim of excessive volume and is subjected to erosion and chronic, uncontrolled flooding. This green infrastructure project will re-establish the natural floodplain wetland and riparian plant communities, which will lead to a species-rich forest community through the removal of invasive species, setting the stage for native plants.

“Over 500 trees and shrubs will be planted in the new wetland with additional trees and shrubs being planted along Lion Gate Drive and in existing woodlands. The selected native plant species all provide important wildlife value such as providing fruit for migratory birds,” Gallagher explained. “We are excited to work with Bloomfield Township to design an urban restoration project that will both enhance the site’s ecological and flood storage value and provide accessibility to the community of Bloomfield.”

It is estimated that Phase One of the project, which includes the wetland construction and plantings, will be completed by September 1, 2019. The maintenance building, concession stand, ball field, etc., will be constructed as part of Phase Two.

“We are very excited to break ground on this exciting project that will have tremendous public benefits, like providing much-needed open space and lowering flood insurance rates for nearby residents and businesses,” said Bloomfield Township Mayor Michael Venezia. “By taking an underutilized parcel of land and turning it into beautiful park and waterfront space to be enjoyed by the public, we are fulfilling our commitment to preserving and enhancing open space. We would not have accomplished this without the efforts of Councilman Nick Joanow, who has advocated for this park for many years, Township Administrator Matthew Watkins, our excellent contractors and environmental experts, and I would like to thank them all. I also want to thank the Department of Environmental Protection and Freshwater Wetlands Mitigation Council for their important grant assistance to help us jump start this complex which will enrich the lives of Bloomfield residents for decades to come.”

NY/NJ Baykeeper has been vital in bringing the project to fruition, having served as an advocate for the project for the last 17 years.

“Lion’s Gate natural restoration is a legitimate all-in-one project that uses green infrastructure and smart planning to address the nested set of urban land use challenges, including: stormwater management, flooding, brownfield cleanup, natural habitat restoration, and the need for both more active playing fields and more passive greenfields,” said Greg Remaud, Baykeeper and CEO, NY/NJ Baykeeper.

Together, Bloomfield Township, Strauss and Associates, ARH, and Princeton Hydro secured $1.76 million in funding for this project from the New Jersey Freshwater Wetlands Mitigation Council and another several million dollars from NJDEP’s Office of Natural Resource Restoration.

To read more about our wetland restoration work, go here: http://bit.ly/PHwetland

 

Part Two: Reducing Flood Risk in Moodna Creek Watershed

Photo of Moodna Creek taken from the Forge Hill Road bridge, New Windsor Post Hurricane Irene (Courtesy of Daniel Case via Wikimedia Commons)

This two-part blog series showcases our work in the Moodna Creek Watershed in order to explore common methodologies used to estimate flood risk, develop a flood management strategy, and reduce flooding.

Welcome to Part Two: Flood Risk Reduction and Stormwater Management in the Moodna Creek Watershed

As we laid out in Part One of this blog series, the Moodna Creek Watershed, which covers 180 square miles of eastern Orange County, New York, has seen population growth in recent years and has experienced significant flooding from extreme weather events like Hurricane Irene, Tropical Storm Lee, and Hurricane Sandy. Reports indicate that the Moodna Creek Watershed’s flood risk will likely increase as time passes.

Understanding the existing and anticipated conditions for flooding within a watershed is a critical step to reducing risk. Our analysis revealed that flood risk in the Lower Moodna is predominantly driven by high-velocity flows that cause erosion, scouring, and damage to in-stream structures. The second cause of risk is back-flooding due to naturally formed and man-made constrictions within the channel. Other factors that have influenced flood risk within the watershed, include development within the floodplain and poor stormwater management.

Now, let’s take a closer look at a few of the strategies that we recommended for the Lower Moodna Watershed to address these issues and reduce current and future flood risk:

Stormwater Management

Damage to Butternut Drive caused when Moodna Creek flooded after Hurricane Irene (Courtesy of Daniel Case via Wikimedia Commons)

Stormwater is the runoff or excess water caused by precipitation such as rainwater or snowmelt. In urban areas, it flows over sewer gates which often drain into a lake or river. In natural landscapes, plants absorb and utilize stormwater, with the excess draining into local waterways.  In developed areas, like the Moodna Creek watershed, challenges arise from high volumes of uncontrolled stormwater runoff. The result is more water in streams and rivers in a shorter amount of time, producing higher peak flows and contributing to flooding issues.

Pollutant loading is also a major issue with uncontrolled stormwater runoff. Population growth and development are major contributors to the amount of pollutants in runoff as well as the volume and rate of runoff. Together, they can cause changes in hydrology and water quality that result in habitat loss, increased flooding, decreased aquatic biological diversity, and increased sedimentation and erosion.

To reduce flood hazards within the watershed, stormwater management is a primary focus and critical first step of the Moodna Creek Watershed Management Plan. The recommended stormwater improvement strategies include:

  • Minimizing the amount of impervious area within the watershed for new development, and replacing existing impervious surfaces with planter boxes, rain gardens and porous pavement.
  • Utilizing low-impact design measures like bioretention basins and constructed-wetland systems that mimic the role of natural wetlands by temporarily detaining and filtering stormwater.
  • Ensuring the long-term protection and viability of the watershed’s natural wetlands.

The project team recommended that stormwater management be required for all projects and that building regulations ensure development does not change the quantity, quality, or timing of run-off from any parcel within the watershed. Recommendations also stressed the importance of stormwater management ordinances focusing on future flood risk as well as addressing the existing flooding issues.

Floodplain Storage

Floodplains are the low-lying areas of land where floodwater periodically spreads when a river or stream overtops its banks. The floodplain provides a valuable function by storing floodwaters, buffering the effect of peak runoff, lessening erosion, and capturing nutrient-laden sediment.

Communities, like the Moodna Creek watershed, can reduce flooding by rehabilitating water conveyance channels to slow down the flow, increasing floodplain storage in order to intercept rainwater closer to where it falls, and creating floodplain benches to store flood water conveyed in the channel.  Increasing floodplain storage can be an approach that mimics and enhances the natural functions of the system.

One of the major causes of flooding along the Lower Moodna was the channel’s inability to maintain and hold high volumes of water caused by rain events. During a significant rain event, the Lower Moodna channel tends to swell, and water spills over its banks and into the community causing flooding. One way to resolve this issue is by changing the grading and increasing the size and depth of the floodplain in certain areas to safely store and infiltrate floodwater. The project team identified several additional opportunities to increase floodplain storage throughout the watershed.

One of the primary areas of opportunity was the Storm King Golf Club project site (above). The team analyzed the topography of the golf course to see if directing flow onto the greens would alter the extent and reach of the floodplain thus reducing the potential for flooding along the roadways and properties in the adjacent neighborhoods. Based on LiDAR data, it was estimated that the alteration of 27 acres could increase floodplain storage by 130.5 acre-feet, which is equivalent to approximately 42.5 million gallons per event.

Land Preservation & Critical Environmental Area Designation

For areas where land preservation is not a financially viable option, but the land is undeveloped, prone to flooding, and offers ecological value that would be impacted by development, the project team recommended a potential Critical Environmental Area (CEA) designation. A CEA designation does not protect land in perpetuity from development, but would trigger environmental reviews for proposed development under the NY State Quality Environmental Review Act. And, the designation provides an additional layer of scrutiny on projects to ensure they will not exacerbate flooding within the watershed or result in an unintentional increase in risk to existing properties and infrastructure.

Conserved riparian areas also generate a range of ecosystem services, in addition to the hazard mitigation benefits they provide. Protected forests, wetlands, and grasslands along rivers and streams can improve water quality, provide habitat to many species, and offer a wide range of recreational opportunities. Given the co-benefits that protected lands provide, there is growing interest in floodplain conservation as a flood damage reduction strategy.


These are just a few of the flood risk reduction strategies we recommended for the Lower Moodna Creek watershed. For a more in-depth look at the proposed flood mitigation strategies and techniques, download a free copy of our Moodna Creek Watershed and Flood Mitigation Assessment presentation.

Revisit part-one of this blog series, which explores some of the concepts and methods used to estimate flood risk for existing conditions in the year 2050 and develop a flood management strategy.

Two-Part Blog Series: Flood Assessment, Mitigation & Management

For more information about Princeton Hydro’s flood management services, go here: http://bit.ly/PHfloodplain

Conservation Spotlight: Reducing Flood Risk and Restoring Wetlands in Jamaica Bay

Located in Queens, New York on the northern shore of Jamaica Bay, Spring Creek South contains approximately 237 acres of undeveloped land, including wetlands and 2.4 miles of coastline. The site is bounded by the Howard Beach residential neighborhood in Queens, a commercial area along Cross Bay Boulevard, the Belt Parkway, and Jamaica Bay. The northwest section of Spring Creek South is part of the National Park Service’s Gateway National Recreation Area, and is largely comprised of small patches of degraded tidal marsh and disturbed and degraded upland ecosystems.

On October 29, 2012, Hurricane Sandy drove a catastrophic storm surge into the New Jersey and New York coastlines. Spring Creek South and the surrounding community of Howard Beach experienced record flooding and damage to property and critical infrastructure. Storm tides caused damage and erosion along the shoreline and in the salt marsh area, degrading important habitat and leaving the site vulnerable to invasive species.

Hurricane Sandy Aftermath at Howard Beach, taken 10/30/2012 by Pam Andrade

The New York State Division of Homeland Security and Emergency Services (NYSDHSES) was awarded funding from FEMA’s Hazard Mitigation Grant Program to restore Spring Creek South. The U.S. Army Corps of Engineers (USACE) New York District, serving as project administrator, contracted Princeton Hydro to provide ecosystem restoration services. The goal of the project is to reduce future flood risk exposure while also protecting, restoring, and improving the quality and function of ecological systems; improving stormwater management and water quality; and enhancing the park’s visitor experience.

To achieve this goal, the project team is using an integrated approach that involves utilizing green infrastructure to create a natural barrier for the community and reduce the risks of coastal storms. Project activities include berm construction and the restoration of tidal marsh, creation of freshwater wetland forest, and creation of maritime shrub, forest, and grassland habitats, as well as stabilization of the existing shoreline.

On December 31, 2018, we completed Phase One of the project, which entails engineering design and preliminary permitting. More specifically, we’ve provided conceptual planning; analysis of subsurface soils for geotechnical properties and hazardous waste; coastal and freshwater wetland delineations; biological benchmarking analysis; and the development of sea level rise curves and two-dimensional hydrologic and hydraulic coastal modeling. As part of the hydrology study, we analyzed what the site could be expected to look like in 50 years due to climate changes and sea level rise. Our engineering design was also brought to 65% completion.

We also obtained permits, prepared the Environmental Assessment (EA), and oversaw the National Environmental Policy Act (NEPA) process. The EA received a “Finding of No Significant Impact” (FONSI) from FEMA, which means the environmental analysis and interagency review concluded that the project has no significant impacts on the quality of the environment.

Due to the complex nature of this project and its location, we are coordinating with a variety of different entities, including the local Howard Beach Community Board, the FAA (proximity to JFK International Airport), Port Authority, USACE, NOAA Fisheries, USFWS, USEPA, NYSDEC, NYC DEP, the National Park Service, HDR Engineering and WSP Engineering.

Phase Two of the project is the construction phase, which is expected to take about two years to complete. A key part of the Spring Creek South construction activities is the restoration of approximately 40 acres of tidal marsh, which is anticipated to improve water quality locally by stabilizing sediment, reducing erosion, and filtering dissolved particulate materials. The project team will restore existing coastline areas and install a salt marsh along the shoreline. Planted with native flora, like Spartina alterniflora, a perennial deciduous grass found in intertidal wetlands, the coastal salt marsh will help to stabilize sediment. Additionally, removing invasive species like Phragmites australis from the area and replacing it with native plant species will increase the ability for native vegetation to colonize the site, improve vegetative diversity, and reduce fire risk in the park.

A forested wetland area and berm will also be created in order to provide the surrounding communities with natural shields and buffers to future storms. The berm, with an elevation of 19 feet (NAVD88), will help to manage the risk of storm surge flooding caused by coastal storms. The forested wetland area will also provide improved stormwater runoff storage, naturally filter stormwater, and, via flap gates, direct its flow toward Jamaica Bay, away from residential and commercial properties.

These measures will help to dissipate wind and wave energy, increase shoreline resilience, improve stormwater management at the site, and create habitat that increases the ecological value and biodiversity at the site, while providing resilience benefits. Restoration activities will benefit vulnerable and rare ecological communities by producing localized environmental enhancements, including improving water quality and creating and restoring habitat. The project also increases opportunities for recreational uses such as wildlife viewing/photography, fishing, and nature study.

Princeton Hydro specializes in the planning, design, permitting, implementing, and maintenance of wetland rehabilitation projects. To learn more about some of our ecosystem restoration and enhancement services, visit: bit.ly/PHwetland.

 

Barnegat “Clean Water, Beautiful Bay” Project wins Governor’s Environmental Excellence Award

The American Littoral Society was awarded the Governor’s Environmental Excellence Award in the Water Resources category this year for their Clean Water, Beautiful Bay projects in Barnegat Bay.

According to the Barnegat Bay Partnership, over 33% of the Barnegat Bay watershed has been altered to urban land cover. The construction of communities, roads and business has greatly increased the total amount of impervious surfaces in the watershed. With the added impervious cover has come a steady increase in the amount of nutrients, sediment, pathogens and other contaminants transported into the Bay by runoff. This accelerated the degradation of the Bay’s water quality and triggered changes to the Bay’s ecology.

Recognizing the importance of the Barnegat Bay, the American Littoral Society proposed green infrastructure measures to decrease runoff volume and nutrient loading to the bay and its tributaries.  Princeton Hydro was contracted by American Littoral Society to design four projects and provide oversight on the construction of the bioretention basins, rain gardens, porous pavement, etc. The projects were funded by the largest 319 grant ever administered by the NJDEP, totaling around $1 million. The project aimed to:

  1. Improve the water quality of Barnegat Bay by reducing the influx of nitrogen and other pollutants originating from the Long Swamp Creek and Lower Toms River watersheds. And, therefore, improve the water quality of both Long Swamp Creek and Lower Toms River, thus moving them closer to removal from the NJDEP’s 303D list of impaired waters.
  2. Demonstrate that relatively low-cost, stormwater system retrofits are capable of decreasing runoff volume, increasing stormwater recharge, and removing nutrients, and can be effectively implemented in even highly developed watersheds.
  3. Educate the public, elected and appointed officials and public work personnel of the types and benefits of bioretention, biodetention and infiltration stormwater management techniques.

From our team, Dr. Steve Souza and Paul Cooper worked to develop a unique Scoring Matrix for the selection of best management practices for retrofit projects. They have been asked several times to present on the matrix and demonstrate how to beneficially utilize it. In addition to design, Princeton Hydro participated in much of the public outreach for these projects, including giving presentations, leading workshops, and helping high school students plant vegetation around their school.

RWJ Barnabas Community Medical Center Educational Sign

According to NJDEP, the Clean Water, Beautiful Bay projects were successful in reducing flooding in a private residential homeowner community, improving a stormwater basin and public open space area at a hospital, introducing golf course staff and golfers to environmentally friendly golf course management practices, and engaging high school students in planting projects on school property.  The projects demonstrated that green infrastructure construction projects can reduce flooding and water pollution at business, community, school and public recreation locations, and can be publicly accepted and valued for the environmentally protective and restorative benefits they provide to Barnegat Bay.

Last year, the American Littoral Society’s Barnegat Bay Green Infrastructure Project was named “Project of the Year” by The American Society of Civil Engineers Central Jersey Branch.

For more information on Princeton Hydro’s green infrastructure and stormwater management services, please visit: bit.ly/stormwatermgmt